Wax as a melt flow modifier and processing aid for polymers

ABSTRACT

An improved method forms and employs a wax to modify throughputs and melt flow in polymers. The method includes: (a) selecting a solid polymeric material, (b) heating the solid polymeric material in an extruder to produce a molten polymeric material, (c) filtering the molten polymeric material, (d) placing the molten polymeric material through a chemical depolymerization process in a reactor to produce a depolymerized polymeric material, and (e) adding the depolymerized material to a pre-wax mixture to produce a modified polymer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority benefits fromInternational application No. PCT/CA2017/050378 filed on Mar. 24, 2017entitled, “Wax as a Melt Flow Modifier and Processing Aid for Polymers”which, in turn, claims priority benefits from U.S. provisional patentapplication No. 62/312,899 filed on Mar. 24, 2016, also entitled “Wax asa Melt Flow Modifier and Processing Aid for Polymers”. The '378 and '899applications are hereby is incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a method of creating synthetic waxesfrom plastic material, and using the waxes to modify new plastics in theprocessing stage. In particular polyethylene plastics, virgin orrecycled, can be modified with waxes to change both their processingthroughput and physical properties such as melt flow index. Increasingthroughput, improves both operation efficiency, and reducesmanufacturing costs. The addition of wax impacting throughput is alsotied to a reduction in extruder backpressure, meaning less equipmentwear. The changes to physical properties, including improving the flowor viscosity of the polymer, have benefits in various fields includinginjection molding, blow molding, rotational molding, compressionmolding, casting, calendaring, blending, milling, and granulation.

BACKGROUND OF THE INVENTION

Additives in polymer processing are commonplace. However, use ofpolyethylene wax to improve the throughput, physical properties andprocessability of polyethylene has not seen extensive use, particularlywith recycled streams. Typical constraints include high cost, and poorblending of polyethylene wax and the polymer.

In recent times, there have been considerable efforts to convertpolymeric solid wastes into useful products. Existing conversionprocesses are not efficient and can release green-house gases into theenvironment.

A low cost method of producing wax that can be employed to achieveimproved processing and more desirable physical characteristics ofspecific polymers, while ensuring good blending of the polyethylenepolymer and the polyethylene wax additive is needed. Such a method wouldideally employ a readily available inexpensive feedstock, preferablyrecyclable material and use an economical process.

SUMMARY OF THE INVENTION

A method for forming a wax and employing the wax to modify polymericprocessing and material properties includes selecting a solid polymericmaterial; heating the solid polymeric material in an extruder to producea molten polymeric material; filtering the molten polymeric material;placing the molten polymeric material through a chemicaldepolymerization process in a reactor to produce a depolymerized waxmaterial; adding the depolymerized wax material into a pre-wax mixtureto produce a modified polymer with an increased melt flow index;filtering the solid polymeric material; cooling the depolymerizedpolymeric material; purifying said depolymerized polymeric material;and/or employing gas and oil produced during purification of thedepolymerized polymeric material as fuel for at least one step of themethod.

In some embodiments, the method is continuous or semi-continuous.

In certain embodiments, the polymeric material is one or more ofhigh-density polyethylene, low density polyethylene, linear low-densitypolyethylene and polypropylene. In some embodiments, the polymericmaterial and/or the pre-wax mixture contains recycled plastics.

In some embodiments, the purifying step is not needed or employs one offlash separation, absorbent beds, clay polishing and film evaporators.In certain embodiments, the depolymerized material is added to thepre-wax mixture via an in-line pump. In certain embodiments, thefiltering step employs a screen changer and/or a filter bed.

In some embodiments, the depolymerization process employs a catalystand/or a second reactor. In certain embodiments, the catalyst issupported on zeolite and/or alumina. In some embodiments, the reactorsare connected in series. In some embodiments, the reactors are stackedvertically. In some embodiments, the reactor comprises a static mixer.

In some embodiments, the pre-wax mixture comprises the solid polymericmaterial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating a process for creating a wax andusing it as a melt flow modifier in polymers.

FIG. 2 is a schematic diagram of a system for producing wax from plasticfeedstocks.

FIG. 3 is a cross-sectional side elevation view of a catalytic reactorwith a removable static mixer configured to be heated via thermalfluid/molten salt.

FIG. 4 is a cross-sectional front elevation view of a group of catalyticreactors of the type shown in FIG. 3, arranged in parallel.

FIG. 5 is a cross-sectional side elevation view of the parallelcatalytic reactor arrangement of FIG. 4 show in a horizontalconfiguration.

FIG. 6 is a cross-sectional side elevation view of a vertical helicalinternal catalytic reactor arrangement with two reactors connected inseries.

FIG. 7 is a perspective view of a horizontal reactor with an internalhelical mixer.

FIG. 8 is a graph illustrating the decrease in amount of pressurerequired to push wax-modified polymeric material through an extruderwhen compared to a non-modified polymeric material.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

A process of converting polymeric material, such as waste polymericmaterial, into wax is described below. This wax can then be employed tomodify polymers. Waxes are compatible with a wide variety of polymermaterial additives, and can be combined with a variety of materialscommonly employed to improve the quality of polymers.

In some embodiments, the addition of the wax improves the processingcharacteristics of the polymer mixture, including improving lubricationof the extruder or processing device which melts the mixture, andincreasing the kilogram per hour throughput of the extruder.

In other or the same embodiments, the addition of wax improves thephysical characteristics of the final product. The resulting finalproducts can have various properties that differ from their unmodifiedforms. In some embodiments, the properties include, among other things,changes in their melt flow indexes (MFI), which in turn modifies theviscosity of the polymer and leads to changes in flow rate when thepolymer is in liquid form.

Some embodiments involve at least two main concepts (1) the creation ofa synthetic wax via depolymerization of plastics and then (2) addingthis wax to modify another plastic. In some embodiments, the plasticstock employed to produce the synthetic wax is the same stock employedto produce the end product plastic.

FIG. 1 illustrates Process 600 for creating synthetic waxes and thenusing those waxes to modify polymers. Process 600 can be run in batches,but more preferably is a continuous process. The parameters of Process600, including but not limited to temperature, flow rate of plastic andtotal number of pre-heat, reaction, or cooling segments, can be modifiedto produce end products of varying molecular weights and structuralproperties. For example, raising the temperature and/or decreasing theflow rate through Wax Creation Stage 2000 will result in waxes of alower molecular weight. Wax Creation Stage 2000 allows for precisetargeting of specific wax characteristics, such as those that maximizethe desire effect of blending.

In Material Selection Stage 1, polymeric feed is selected and/orprepared for treatment. In some embodiments, the polymeric feed issorted/selected to include polyethylene material. The polymer can beHDPE, LDPE, LLDPE, and/or other variations of polyethylene.

In other embodiments, the polymeric feed in sorted/selected to includepolypropylene material. In other embodiments, the polymeric feed issorted/selected to include both polyethylene and polypropylene material.In some embodiments, the feed can contain up to 20% polypropylene, lowerlevels of polystyrene PET, EVA, PVC, EVOH, and undesirable additivesand/or contaminants, such as fillers, dyes, metals, various organic andinorganic additives, moisture, food waste, dirt, or other contaminatingparticles.

In some embodiments, the material selected in Material Selection Stage 1comprises recycled plastics. In other or the same embodiments, thematerial selected in Material Selection Stage 1 comprises recycledplastics and/or virgin plastics.

The polymeric feed for Material Selection Stage 1 can come from eitherPlastic Feed A1 or Plastic Feed A2. When the feed comes from PlasticFeed A2, the resulting wax can have a similar composition when it isadded with more plastic from Plastic Feed A2 to create Final Plastic E.This leads to a more homogenous product with improved throughput andmelt flow modification.

In some embodiments, the material selected in Material Selection Stage 1is heated in an extruder in Heat Stage 2 and undergoes Pre-FiltrationProcess 3. In some embodiments, the extruder is employed to increase thetemperature and/or pressure of the incoming plastic and/or is employedto control the flow rates of the plastic. In some embodiments, theextruder is complimented by or replaced entirely by a pump/heaterexchanger combination.

Pre-Filtration Process 3 can employ both screen changers and/or filterbeds, along with other filtering techniques/devices to removecontaminants from and purify the heated material. The resulting filteredmaterial is then moved into an optional Pre-Heat Stage 4 which bringsthe filtered material to a higher temperature before it entersDepolymerization Stage 5. Pre-Heat Stage 4 can employ, among otherdevices and techniques, static mixers and/or heat exchangers such asinternal fins and/or heat pipes.

Material in Depolymerization Stage 5 undergoes depolymerization. Thisdepolymerization can be a purely thermal reaction or it can employcatalysts. Depending on the starting material and the desired endproduct, depolymerization can be employed for a slight or extremereduction of the molecular weight of the starting material.

In some embodiments, the catalyst employed is a zeolite or aluminasupported system or a combination of the two. In some embodiments, thezeolite contains aluminum oxide. In some embodiments, the catalyst isprepared by binding a ferrous-copper complex to an alumina or zeolitesupport and reacting it with an inorganic acid.

Depolymerization Stage 5 can employ a variety of techniques/devicesincluding, among other things, horizontal and/or vertical fixed bedreactors, and/or static mixers. In some embodiments, Reaction Stage 5employs multiple reactors and/or reactors divided into multiple sectionsto produce a semi-continuous or continuous process.

After Depolymerization Stage 5, the depolymerized material either entersCooling Stage 6 or is pumped via In-line Pump 8 directly into Extruder 9where it is mixed with plastic from Plastic Feed A2 to create FinalPlastic E.

Cooling Stage 6 can employ heat exchangers, along with othertechniques/devices to bring the depolymerized material down to aworkable temperature before it enters optional Purification Stage 7 oris pumped via In-line Pump 8 and mixed with plastic from Plastic Feed A2to create Final Plastic E.

In some embodiments, cleaning/purification of the material via suchmethods such as nitrogen stripping occurs before Cooling Stage 6.

Purification Stage 7 involves the refinement and/or decontamination ofthe depolymerized material. Techniques/devices that can be employed inPurification Stage 7 include, but are not limited to, flash separation,absorbent beds, clay polishing, distillation, vacuum distillation and/orfiltration to remove solvents, oils, color bodies, ash, inorganics,and/or coke.

In some embodiments, a thin or wiped film evaporator is employed toremove gas, oil, and/or grease from the depolymerized material. In someembodiments, the oil, gas and grease can in turn be burned to help runvarious Stages of Process 2000.

In some embodiments, the purified material is pumped via In-line Pump 8directly into Extruder 9 where it is mixed with plastic from PlasticFeed A2 to create Final Plastic E. In other embodiments, the purifiedmaterial is processed as a solid Wax C that can then be employed as WaxFeed B in Plastic Modification Stage 3000.

Wax Creation Stage 2000 ends at Wax C in which the initial startingmaterial selected in Material Selection Stage 1 has been turned into WaxC. In at least some embodiments, Wax C is included as part of Wax FeedB. In some embodiments, Wax C is not highly branched and instead has amore linear structure.

Plastic Modification Stage 3000 involves combining plastic from PlasticFeed A2 with a synthetic wax. In some embodiments, the synthetic wax istaken from Wax Feed B and mixed together with Plastic from Plastic FeedA2 to form Plastic/Wax Feed D which is then sent to Extruder 9 beforebecoming Final Plastic E. In some embodiments, the wax in Wax Feed B wascreated via Wax Creation Stage 2000. In some embodiments, the percentageof wax in the wax/plastic compound is roughly 1 to 8 percent.

In other embodiments, plastic from Plastic Feed A2 is mixed directlywith hot wax coming from Wax Creation Stage 2000. This method allows forseveral steps in the process to be eliminated such as cooling the wax(Cooling Stage 6) and/or transporting the wax from one location toanother.

Referring to FIG. 2, System 1000 includes reactor 700 with five reactormodules 102(a) through 102(e). Reactor modules 102 can vary indimensions and/or be connected in parallel and/or series. In otherembodiments, various numbers of reactor modules 102 can be employed. Theability to customize the number of reactor modules 102 allows forgreater control of the amount of depolymerization. System 1000 is oftenemployed in Wax Creation Stage 2000.

System 1000 can include hopper 111 for receiving polymeric materialand/or directing the supply of the polymeric material to optionalextruder 106. In some embodiments, extruder 106 processes the polymericmaterial received from hopper 111 by generating a molten polymericmaterial. The temperature of the polymeric material being processed byextruder 106 is controlled by modulating the level of shear and/or theheat being applied to the polymeric material by extruder heater(s) 105.Extruder heaters can use a variety of heat sources including, but notlimited to, electric, thermal fluids, and/or combustion gases. The heatcan be modulated by a controller, in response to temperatures sensed bytemperature sensor(s) 107.

In some embodiments, pressure sensor 109 measures the pressure of themolten polymeric material being discharged from extruder 106, toprevent, or at least reduce, risk of pressure spikes. The dischargedmolten polymeric material can be pressurized by pump 110 to facilitateits flow through heating zone 108 and reactor 100. While flowing throughreactor 100, the reactor-disposed molten polymeric material can contacta catalyst material which causes depolymerization.

Pressure sensor(s) 109 and/or temperature sensor(s) 107 can also beemployed to measure temperature and/or pressure, respectively, of thereactor-disposed molten polymeric material as it flows through reactor100. Pressure sensor(s) 109 can monitor for plugs before and/or aftereach reaction zones. Pressure sensor(s) 109 can also maintain systempressure below a maximum pressure such as the maximum pressure ofreactor 700 is designed for. Over-pressure can be controlled by feedbackfrom pressure transmitter 109 to a controller which transmits a commandsignal to shut down extruder 106 and pump 110, and thereby prevent thepressure from further increasing.

In cases when shutdown of extruder 106 does not relieve the overpressure, dump valve 117 can be opened into a container to removematerial from system 1000 and avoid an over pressure situation. Duringshutdown dump valve 117 can be opened to purge system 1000 with nitrogento remove leftover material to avoid clogs and degraded material duringthe next start up.

System 1000 can also include a pressure relief device, such as a reliefvalve or a rupture disk, disposed at the outlet of extruder 106, torelieve pressure from system 1000, in case of over-pressure.

Temperature sensor(s) 107 can facilitate control of the temperature ofthe reactor-disposed molten polymeric material being flowed throughreactor 100. This allows more precise control of the chemical reactionand the resulting polymerization. Temperature sensor(s) 107 also aid inmaintaining the temperature below a predetermined maximum temperature,for example the maximum design temperature of reactor 100.

The temperature is controlled by a controller (not shown), whichmodulates the heat being applied by heaters 118 disposed in heattransfer communication with reaction zones 102(a) through 102(e) ofreactor 100, in response to the temperatures sensed by temperaturesensor(s) 119.

System 1000 can also include a pressure relief device, such as a reliefvalve or a rupture disk, disposed at the outlet of extruder 106, torelieve pressure from system 10, in case of over-pressure.

Flow control can also be provided for within system 1000. In someembodiments, system 1000 includes valve 115, disposed at the dischargeof extruder 106, for controlling flow from extruder 106 to other unitoperations within system 1000. Valve 116 facilitates recirculation.Valve 117 enables collection of product.

During operation, valve 115 can be closed in order to recirculate themolten polymeric material and increase the temperature of the moltenpolymeric material to a desired temperature. In this case valve 116would be open, valve 117 would be closed, extruder 106 would be “OFF”,and pump 110 would be recirculating.

Generated molten product material 112 is cooled within heat exchanger114, which can be, among other ways, water jacketed, air cooled, and/orcooled by a refrigerant. A fraction of the cooled generated moltenproduct material can be recirculated (in which case valve 116 would beopen), for reprocessing and/or for energy conservation.

In some embodiments, system 1000 is configured for purging by nitrogento mitigate oxidation of the molten product.

In System 1000 reactor 700 includes one or more reactor modules. Eachreactor modules includes a respective module reaction zone in which thereactor-disposed molten polymeric material is brought into contact witha catalyst material over a module-defined residence time, therebycausing depolymerization of the flowing reactor-disposed moltenpolymeric material. In some of these embodiments, the module-definedresidence time of at least two of the reactor modules is the same orsubstantially the same. In some of these embodiments, at least some ofthe plurality of module-defined residence times are different. In someembodiments, the catalyst material of at least two of the reactormodules is the same or substantially the same. In other embodiments, thecatalyst material of at least two of the reactor modules is different.

In some embodiments, each of the reactor modules includes areactor-disposed molten polymeric material-permeable container thatcontains the catalyst material. The container can be configured toreceive molten polymeric material such that at least partialdepolymerization of at least a fraction of the received molten polymericmaterial is affected by the catalyst material, and to discharge a moltenproduct material that includes depolymerization reaction products (andcan also include unreacted molten polymeric material and intermediatereaction products, or both). Flowing of the reactor-disposed moltenpolymeric material through the reactor-disposed molten polymericmaterial-permeable container affects contacting between the catalystmaterial and the reactor-disposed molten polymeric material, foraffecting the at least partial depolymerization of at least a fractionof the reactor-disposed molten polymeric material. In this respect, theflowing reactor-disposed molten polymeric material permeates through thecatalyst material within the container, and while permeating through thecatalyst material, contacts the catalyst material contained within thecontainer, for affecting the at least partial depolymerization of atleast a fraction of the reactor-disposed molten polymeric material.

In System 1000 a first reactor is assembled from the reactor modules.The first reactor has a first reaction zone and includes a total numberof “P” reactor modules from “N” reactor modules, wherein “N” is a wholenumber that is greater than or equal to one.

Each one of the “N” reactor modules defines a respective module reactionzone including a catalyst material disposed therein, and is configuredfor conducting a flow of reactor-disposed molten polymeric materialthrough the respective module reaction zone, such that, flowing of thereactor-disposed molten polymeric material through the respective modulereaction zone brings it into contract with the catalyst material,thereby causing at least partial depolymerization of at least a fractionof the flowing reactor-disposed molten polymeric material. In thisrespect, the first reaction zone includes “P” module reaction zones.

When “N” is a whole number that is greater than or equal to two, eachone of the “N” reactor modules is configured for connection, in series,to one or more of the other “N” reactor modules such that a plurality ofreactor modules are connected to one another, in series, and includes aplurality of module reaction zones that are disposed in fluidcommunication within one another, in series, such that the total numberof module reaction zones correspond to the total number of connectedreactor modules. The plurality of connected reactor modules isconfigured for conducting a flow of reactor-disposed molten polymericmaterial through the plurality of module reaction zones, such that itcomes into contact with the catalyst material, thereby affecting atleast partial depolymerization of at least a fraction of the flowingreactor-disposed molten polymeric material.

When “P” is a whole number that is greater than or equal to two, theassembling of the first reactor includes connecting the “P” reactormodules to one another, in series, such that “P” reaction zones aredisposed in fluid communication with one another in series.

In the embodiment illustrated in FIG. 2, “P” is equal to five, such thatreactor 700 includes five reactor modules 102(a) through 102(e), thereaction zone consisting of five module reaction zones 104(a) through104(e), each one respective to a one of the five reactor modules. “P”can be more or less than five.

Molten polymeric material, for supplying to the constructed reactor, isgenerated by heating a polymeric material. In some embodiments, theheating is caused by a heater. In FIG. 2 the heating is produced by acombination of extruder 106 and separate heater 108. In suchembodiments, the generated molten polymeric material is forced from theextruder, flowed through a separate heater, and then supplied to themodule reaction zone. In some embodiments, the extruders are configuredto supply sufficient heat to the polymeric material such that thegenerated molten polymeric material is at a sufficiently hightemperature for supply to the reactor, and a separate heater is notrequired.

In FIG. 2, pump 110 receives molten polymeric material from extruder 106and affects transport (or flowing) of the molten polymeric materialthrough heater 108, and then through the first reaction zone. In someembodiments, extruder 106 is configured to impart sufficient force toaffect the desired flow of the generated molten polymeric material, suchthat pump 110 is optional.

In some embodiments, the molten polymeric material is derived from apolymeric material feed that is heated to affect generation of themolten polymeric material. In some embodiments, the polymeric materialfeed includes primary virgin granules of polyethylene. The virgingranules can include low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), high density polyethylene (HDPE), polypropylene(PP), or a mixture including combinations of LDPE, LLDPE, HDPE, and PP.

In some embodiments, the polymeric material feed includes wastepolymeric material feed. Suitable waste polymeric material feeds includemixed polyethylene waste, mixed polypropylene waste, and a mixtureincluding mixed polyethylene waste and mixed polypropylene waste. Themixed polyethylene waste can include low density polyethylene (LDPE),linear low density polyethylene (LLDPE), high density polyethylene(HDPE), polypropylene (PP), or a mixture including combinations of LDPE,LLDPE, HDPE and PP. In some embodiments, the mixed polyethylene wastecan include film bags, milk jugs or pouches, totes, pails, caps,agricultural film, and packaging material. In some embodiments, thewaste polymeric material feed includes up to 10 weight % of materialthat is other than polymeric material, based on the total weight of thewaste polymeric material feed.

The molten polymeric material is supplied to the reactor, and the moltenpolymeric material is flowed through the first reaction zone (i.e.including the “P” reaction zones) as reactor-disposed molten polymericmaterial. The flowing of the reactor-disposed molten polymeric materialthrough the first reaction zone brings it into contact with the catalystmaterial generating a molten product material, including adepolymerization product material (and, in some embodiments, alsoincludes unreacted molten polymeric material and/or intermediatereaction products). The molten product material is then collected.

In some embodiments, the catalyst is prepared by binding aferrous-copper complex to an alumina support and reacting it with aninorganic acid to obtain the catalyst material. Other suitable catalystmaterials include zeolite, mesoporous silica, alumina, H-mordenite andvarious combinations. The system can also be run in the absence of acatalyst and produce waxes through thermal degradation.

The generated molten product material is discharged from andcollected/recovered from the reactor. In some embodiments, thecollection of the molten product material is affected by discharging aflow of the molten product material from the reactor. In thoseembodiments, with a plurality of reactor modules, the molten productmaterial is discharged from the first reactor module and supplied to thenext reactor module in the series for affecting further depolymerizationwithin the next reactor module in the series, and this continuesas-between each adjacent pair of reactor modules in the series.

In some embodiments, the generated depolymerization product materialincludes waxes, greases, oils, fuels, and C1-C4 gases, and grease-basestocks. Commercially available greases are generally made by mixinggrease base stocks with small amounts of specific additives to providethem with desired physical properties. Generally, greases include fourtypes: (a) admixture of mineral oils and solid lubricants; (b) blends ofresiduum (residual material that remains after the distillation ofpetroleum hydrocarbons), uncombined fats, rosin oils, and pitches; (c)soap thickened mineral oils; and (d) synthetic greases, such aspoly-alpha olefins and silicones.

In some embodiments, the polymeric feed material is one of, or acombination of, virgin polyethylene (any one of, or combinations of,HDPE, LDPE, LLDPE and medium-density polyethylene (MDPE)), virginpolypropylene, or post-consumer, or post-industrial, polyethylene orpolypropylene (exemplary sources including bags, jugs, bottles, pails,and/or other items containing PE or PP), and it is desirable to convertsuch polymeric feed material into a higher melting point wax (having amelting point from 106° C. to 135° C.), a medium melting point wax(having melting point from 86° C. to 105° C.), and a lower melting pointwax (having a melting point from 65° C. to 85° C.), an even lowermelting point wax (having a melting point from 40° C. to 65° C.), usingan embodiment of the system disclosed herein.

In each case, the conversion is effected by heating the polymeric feedmaterial so as to generate molten polymeric material, and thencontacting the molten polymeric material with the catalyst materialwithin a reaction zone disposed at a temperature of between 325° C. and450° C. The quality of wax (higher, medium, or lower melting point wax)that is generated depends on the residence time of the molten polymericmaterial within the reaction zone. When operating in a continuous systemdepending on the flowrate of the extruder or gear pump residence timesvary from 1-120 minutes, preferably 5-60 minutes, with 1-12 reactormodules attached in series. In some of these embodiments, the supply andheating of the polymeric feed material is affected by a combination ofan extruder and a pump, wherein the material discharged from theextruder is supplied to the pump. In some of these embodiments, extruder106 is a 10 HP, 1.5 inch (3.81 cm) Cincinnati Milacron PedestalExtruder, Model Apex 1.5, and the pump 110 is sized at 1.5 HP for a 1.5inch (3.81 cm) line.

A pressure transducer PT01 monitors for plugs within the extruder (aswell as prior to PT02, see below) for maintaining system pressure belowa maximum pressure (namely, the maximum design pressure of the reactor100). Likewise, pressure transducer PT02 monitors for plugs elsewherewithin the system. Over-pressure is controlled by feedback from thepressure transmitted by PT01 and PT02 to a controller which transmits acommand signal to shut down the extruder 106 and the pump 110, andthereby prevent the pressure from further increasing.

In some embodiments, reactor 100 is first reactor 100, and the reactionzone of the first reactor is a first reaction zone, and the flowing ofthe molten polymeric material, through the first reaction zone, issuspended (such as, for example, discontinued).

When “P” is equal to one, the modifying includes connecting a totalnumber of “R” of the “N−1” reactor modules, which have not been used inthe assembly of the first reactor, to the first reactor, in which “R” isa whole number from 1 to “N−1”, such that another reactor is added andincludes a total number of “R+1” reactor modules that are connected toone another, in series, and such that the another reactor includes asecond reaction zone including “R+1” module reaction zones. Then anotherreactor is configured to conduct a flow of molten polymeric material,such that flowing of the reactor-disposed molten polymeric materialthrough the second reaction zone affects generation of anotherdepolymerization product material and its discharge from the anotherreactor.

When “P” is a whole number that is greater than or equal to two, butless than or equal to “N−1”, the modifying includes either one of:

-   -   (a) removing a total number of “Q” of the “P” reactor modules        from the first reactor, wherein “Q” is a whole number from one        to “P−1”, such that another reactor is added and includes a        total number of “P−Q” reactor modules that are connected to one        another, in series, and such that the another reactor includes a        second reaction zone including “P−Q” module reaction zones,        wherein the another reactor is configured to conduct a flow of        molten polymeric material, such that flowing of the        reactor-disposed molten polymeric material through the second        reaction zone affects generation of another depolymerization        product material and its discharge from the another reactor, or    -   (b) connecting a total number of “R” of the “N−P” reactor        modules, which have not been employed in the assembly of the        first reactor, to the first reactor, wherein “R” is a whole        number from 1 to “N−P”, such that another reactor is added and        includes a total number of “P+R” reactor modules that are        connected to one another, in series, and also includes a second        reaction zone including “P+R” module reaction zones, wherein the        another reactor is configured to conduct a flow of molten        polymeric material, such that flowing of the reactor-disposed        molten polymeric material through the second reaction zone        affects generation of another depolymerization product material        and its discharge from the another reactor.

When “P” is equal to “N”, the modifying includes removing a total numberof “Q” of the “P” reactor modules from the first reactor, wherein “Q” isa whole number from one to “P−1”, such that another reactor is added andincludes a total number of “P−Q” reactor modules that are connected toone another, in series, and such that the another reactor includes asecond reaction zone, including “P−Q” module reaction zones. The anotherreactor is configured to conduct a flow of molten polymeric material,such that flowing of the reactor-disposed molten polymeric materialthrough the second reaction zone affects generation of anotherdepolymerization product material and its discharge from the anotherreactor.

In some embodiments, after the modifying of the first reactor to affectcreation of another reactor (by either one of connecting/adding orremoving reactor modules), another reactor is employed to generate asecond depolymerization product material. In this respect, polymericmaterial is heated to generate a molten polymeric material, and themolten polymeric material is flowed through the second reaction zone, toaffect generation of a second depolymerization product material. Thesecond depolymerization product material is then collected from thereactor.

In some embodiments, the same catalyst material is disposed within eachone of the “N” reactor modules.

In some embodiments, the reaction zone of each one of the “N” reactormodules is the same or substantially the same.

FIG. 3 shows a cross-section side-elevation view of catalytic reactor700 with removable static mixer 710 configured to be heated via thermalfluid and/or molten salt. Static mixer 710 provides greater mixing incatalytic reactor 700 and can result in the need of a lower operatingtemperature. In other embodiments, catalytic reactor 700 can include anannular insert. In other embodiments, catalytic reactor 700 can haveempty internals. In certain embodiments, catalytic reactor 700 employselectric heating.

The tubular configuration of catalytic reactor 700 offers severaladvantages in addition to those already mentioned. In particular, use oftubular reactors connected in series allows for dependable andconsistent parameters, which allows for a consistent product.Specifically, a consistent flow through the tubular sections produces amore predictable and narrow range of end products than would be producedusing a continuous stirred reactor, as the surface area of the catalystand heat input is maximized. One advantage over continuous stirredreactors is elimination of shortcutting, flow in tubular sectionhypothetically moves as a plug. Each hypothetical plug spends the sameamount of time in the reactor. Tubular catalytic reactors can beoperated vertically, horizontally, or at any angle in between. Tubularcatalytic reactors (the reactor sections) and the corresponding pre-heatsections and cooling sections can be a universal size or one of severalstandard sizes. This allows not only for a consistent flow of thematerial, but also allows for tubular elements to be designed to beinterchangeable among the various section and easily added, removed,cleaned, and repaired. In at least some embodiments, the inner face ofthe tubular sections is made of 304 or 316 steel.

The thermal fluid and/or molten salt can enter jacket 720 viainlet/outlets 730. In some embodiments, catalytic reactor 700 a isconfigured to be mounted with a thermocouple/pressure transducer (notshown) and includes relevant notches 735. Notches 735 are employed tobring the thermocouple/pressure transducer in physical contact with thefluid. In some embodiments, the thermocouple/pressure transducer can bemounted in a well, which reduces the material in-between the fluid andthe sensor.

In some embodiments, catalytic reactor 700 includes removable screen 760that can hold the catalyst. Removable screen 760 can be easily replacedovercoming disadvantages associated with packed bed reactors, includingthermal gradients and challenging maintenance requirements and resultingdowntime. In some embodiments, the standardization of removable screen760 results in a consistent product leaving each section and/or allowsfor standardization across multiple reactors.

In other or the same embodiments, catalytic reactor 700 a can includeremovable adaptor 740 with cut-outs for static mixer supports. Staticmixer supports reduce the force on static mixers 710 allowing for moreforceful/rapid removal. The cut-outs of adaptor 740 improve the sealbetween the adapter and the screens. Catalytic reactor 700 a can includeflanges 750 on one or both ends to connect catalytic reactor 700 a toother reactors, extruders or the like.

FIG. 4 is a cross-section front-elevation view of a group of catalyticreactors 700 like the one shown in FIG. 3 arranged in parallel. Parallelarrangements allow for the total rate of production to be more readilyincrease/decreased as desired with minimal changes to the overallarrangement and allow multiple different levels of depolymerization tooccur at once.

Housing 800 allows catalytic reactors 700 to be bathed in thermaloil/molten salt which is often more effective than electric. The thermaloil/molten salt is contained in chamber 780. In some embodiments, flange770 allows for multiple housings to be joined together.

FIG. 5 is a cross-section side-elevation view of the parallel catalyticreactor arrangement of FIG. 25 show in a horizontal configuration.Parallel arrangement allows for higher flowrate units to be built withsmaller pressure drops that could cause issues as compared to a singletube arrangement. Horizontal configurations are often more convenient tooperate/maintain. The parallel catalytic reactor arrangement can also beoriented in a vertical configuration.

FIG. 6 is a cross-section side-elevation view of vertical helicalinternal catalytic reactor arrangement 500 with two reactors 700 likethe one shown in FIG. 3 connected in series. Horizontal helical mixerpre-heat section 820 is connected to one reactor 700. Helical mixers canlead to better mixing by avoiding stagnancies and hot spots.

Helical mixer cooling segment 830 is shown connected to the otherreactor 700 at a 45° decline. The decline allows for the product to flowvia gravity, while the 45° angle allows for sufficient contact betweenthe cooling medium and the product.

In the embodiments shown, vertical helical internal catalytic reactorarrangement 500 has several inlets/outlets to allow for the use ofthermal fluid/molten salt mixtures however other warming techniques(such as, but not limited to, electric heating) can be employed as well.In other embodiments, annular catalytic reactor and/or reactors withempty internal volumes can be employed. In the same or otherembodiments, electric heating can be employed to heat reactor 700.

FIG. 7 is a perspective view of horizontal reactor configuration 910with internal helical reactor 700 configured to employ electric heaters870 like the one shown in FIG. 3. In FIG. 7 the reactor shell has beenremoved from part of horizontal reactor configuration 910 to aid invisualizing the location of internal helical reactor 700

Specific Examples of Plastics Modified by Synthetic Waxes

TABLE 1 Materials Used Ingredient Grade/Type Source Control PlasticClean PCR Pellet (HDPE milk jugs) KW Plastics Wax A AW125 Applicant WaxB AW105LV Applicant

Example 1

In a first illustrative embodiment of the present process, wax wasproduced from the depolymerization of post-consumer polyethylene.Various percentages of the wax (by weight of the wax) were mixed with arecycled plastic (HDPE clear milk jugs). The melt flow rate of theresulting products was increased, leading to greater output.

In the above embodiment, blending/extrusion was conducted on a TEC 1.5″single screw extruder. Melt flow index testing was conducted on anArburg Injection Machine with a 3 MM plaque mold. Barrel diameter was9.5320 mm, die length was 8.015 mm, and orifice diameter was 2.09 mm. Asix-minute preheat was utilized. Melt Flow index testing was conductedper ASTM D1238: Standard Test Method For Flow Rates Of Thermoplastics at190° C. and 2.16 Kg Load.

The preparation and testing of the blends in Example 1-3 were asfollows.

-   -   (1) The materials were blended with waxes to create the        following mixtures        -   Control (100% Control Plastic)        -   Mixture A (92% Control Plastic with 8% Wax A)        -   Mixture B (92% Control Plastic with 8% Wax B)        -   Mixture C (98% Control Plastic with 2% Wax A)    -   (2) The mixtures were extruded into pellets (screen pack start        40/100/40)    -   (3) The pressure, temperatures, and throughput (time to weight)        were recorded.    -   (4) Amps were recorded every 10 minutes.    -   (5) The final extruded mixtures were tested for melt flow.

Graph 900 in FIG. 8 illustrates the decrease in amount of pressurerequired to push the wax-modified polymeric material 920 through anextruder when compared to a non-modified polymeric material 910.

TABLE 2 Wax Modified Polymer Results (Example 1) Con- Mix- Mix- Mix-Property trol ture A ture B ture C Incoming Material 0.0048 N/A N/A N/AMoisture (%) Incoming Material Melt 0.604 N/A N/A N/A Flow Rate (g/10mins) Pre Extrusion Parts 0.0071 0.0074 0.0079 0.0189 Moisture (%) PreExtrusion Parts Melt 0.563 0.759 0.767 0.590 Flow Rate (g/10 mins)Pellet Material Moisture 0.0051 0.0062 0.0064 0.0029 (%) Pellet MaterialMelt 0.622 0.954 0.916 0.639 Flow Rate (g/10 mins) Throughput (lbs/hour)31.4 38.2 39.3 36.1 Percent Increase in N/A 22 25 11 Throughput vs.Control Average Temperature 214.6 218 216 211.9 (° C.) Average (PSI)852.46 736.16 777.95 629.43 Percent Reduction in N/A −14 −9 −10 Pressurevs Control

Example 2

In Example 2, a polyethylene wax was mixed in different ratios (1%, 3%,5%) with HDPE polymer. It was found that increasing the quantity of waxresulted in an increase in the melt flow index of the wax/polymermixture.

In one embodiment the initial HDPE had an initial melt flow index (MFI)of 0.40 grams/10 minutes (following ASTM D1238). The HDPE was thenconverted into a polyethylene wax, and was mixed into the same HDPE at aconcentration of 1 wt %. The MFI of the HDPE/wax mixture was increasedto 0.42 grams/10 minutes.

In another embodiment, the initial HDPE was mixed with the polyethylenewax at a concentration of 5 wt %. The MFI of the HDPE/wax mixture wasincreased to 0.53 grams/10 minutes.

In the above embodiments, blending/extrusion was conducted on aMerritt-Davis 2″ extruder. Melt flow index testing was conducted on aGoettfert Melt Indexer. Barrel diameter was 9.5320 mm, die length was8.015 mm, and orifice diameter was 2.09 mm. A six-minute preheat wasutilized. Melt Flow index testing was conducted per ASTM D1238: StandardTest Method For Flow Rates Of Thermoplastics at 190° C. and 2.16 KgLoad.

TABLE 3 Melt Flow Index Results (Example 3) Sample Melt Flow Index (g/10min) Control 0.40 1% wax A 0.42 3% wax A 0.45 5% wax A 0.53

Example 4

In Example 4, a polyethylene wax (applicant's A120) was mixed indifferent ratios (2% and 4%) with a post consumer regrind high-densitypolyethylene natural bottle flake (PCR HDPE) supplied by Envision. Itwas found that increasing the quantity of wax resulted in an increase inthe elongation average. Test were conducted with both controlled screwspeed (125 revolution per minute) and under controlled pressure (˜125bar).

TABLE 4 Commercial Extrusion Evaluation Trial Run Averages (Example 4)Average Average Average Average Temp Pressure Energy Output Sample (C.)(bar) (kW) (kg/hr) Control 249 122 68.482 131.1 125 RPM 2% wax D 250 11054.712 132.9 125 RPM 2% wax D 248 126 72.373 166.0 165 RPM 4% wax D 250108 58.878 129.3 125 RPM 4% wax D 248 124 70.295 167.8 170 RPM

Table 4 shows that as wax is added, the melt flow increases. Running theprocess at constant revolution per minute decreases pressure in thesystem, and the amount of energy needed compared to the control as themixture has an increased flow rate. Keeping pressure constant increasesthe output relative to the control.

TABLE 5 Injection Molded Data (Example 4) Flexural Pellet Melt IZODTensile Elongation Modulus Flow Rate (lbf- at yield Average Sample (bar)(g/10 mins) ft/in) (bar) (%) Control 11338 0.47 10.20 262 374 2% wax D11606 0.63 11.44 270 444 4% wax D 11482 0.63 10.20 259 607

In one embodiment, the mixtures from Table 4 were injected into a mold.The initial PCR HDPE had an elongation average of 374%.

In one group the PCR HDPE was mixed with the polyethylene wax at aconcentration of 2 wt %. The resulting PCR HDPE mixture had anelongation average of 444%.

In another group the PCR HDPE was mixed with the polyethylene wax at aconcentration of 4 wt %. The resulting PCR HDPE mixture had anelongation average of 607%

The following conclusions can be drawn from the foregoing test results:

The addition of waxes derived from thermal or catalytic depolymerizationof plastics have at least some of the following impacts on polymerprocessing or reprocessing:

-   -   increases the melt flow index of a polymer    -   higher throughput rates    -   less backpressure and equipment wear    -   improved internal lubrication    -   strong external lubrication    -   increased elongation averages when being used for injection        molding

While particular elements, embodiments and applications of the presentinvention have been shown and described, it will be understood, that theinvention is not limited thereto since modifications can be made withoutdeparting from the scope of the present disclosure, particularly inlight of the foregoing teachings.

What is claimed is:
 1. A method for forming a depolymerized wax andemploying said depolymerized wax to modify polymeric processing andmaterial properties, the method comprising: selecting a solid polymericpost-consumer or post-industrial feed; heating said solid polymericpost-consumer or post-industrial feed in an extruder to produce a moltenpolymeric material; filtering said molten polymeric material; placingsaid molten polymeric material through a chemical depolymerizationprocess in a reactor to produce a depolymerized wax material, whereinthe depolymerized wax material has a melting point between 106° C. and135° C.; adding said depolymerized wax material into a pre-wax mixtureto produce a modified polymer with an increased melt flow index, whereinsaid pre-wax material comprises a polymer.
 2. The method of claim 1,wherein said method is continuous or semi-continuous.
 3. The method ofclaim 1, further comprising: filtering said solid polymericpost-consumer or post-industrial feed.
 4. The method of claim 1, furthercomprising: cooling said depolymerized wax material.
 5. The method ofclaim 4, further comprising: purifying said depolymerized wax material.6. The method of claim 5, wherein said purifying step employs one offlash separation, absorbent beds, clay polishing and film evaporators.7. The method of claim 1, wherein said depolymerized wax material isadded to said pre-wax mixture via an in-line pump.
 8. The method ofclaim 3, wherein said filtering step employs a filter bed.
 9. The methodof claim 1, wherein said depolymerization process employs a catalyst.10. The method of claim 9, wherein said catalyst is supported on zeoliteor alumina.
 11. The method of claim 1, wherein said depolymerizationprocess employs a second reactor.
 12. The method of claim 11, whereinsaid reactors are connected in series.
 13. The method of claim 11,wherein said reactors are stacked vertically.
 14. The method of claim 1,wherein said reactor comprises a static mixer.
 15. The method of claim1, wherein said solid polymeric post-consumer or post-industrial feedincludes recycled polyethylene.
 16. The method of claim 1, wherein solidpolymeric post-consumer or post-industrial feed includes recycledpolypropylene.
 17. The method of claim 1, wherein said solid polymericpost-consumer or post-industrial feed includes inorganics.
 18. Themethod of claim 1, wherein the amount of said depolymerized wax materialmixed into said pre-wax mixture is between 1 to 5 percent of the weightof said modified polymer.
 19. A method for forming a depolymerized waxand employing said depolymerized wax to modify polymeric processing andmaterial properties, the method comprising: selecting a solid polymericpost-consumer or post-industrial feed; heating said solid polymericpost-consumer or post-industrial feed in an extruder to produce a moltenpolymeric material; filtering said molten polymeric material; placingsaid molten polymeric material through a chemical depolymerizationprocess hi a reactor to produce a depolymerized wax material, whereinthe depolymerized wax material has a melting point between 106° C. and135° C.; adding said depolymerized wax material into a pre-wax mixtureto produce a modified polymer with an increased melt flow index, whereinsaid pre-wax mixture comprises said solid polymeric post-consumer orpost-industrial feed which has not been depolymerized.
 20. A method forforming a depolymerized wax and employing said depolymerized wax tomodify polymeric processing and material properties, the methodcomprising: selecting a solid polymeric post-consumer or post-industrialfeed, wherein said solid polymeric post-consumer or post-industrial feedcomprises recycled polyethylene and inorganics; heating said solidpolymeric post-consumer or post-industrial feed in an extruder toproduce a molten polymeric material; filtering said molten polymericmaterial; placing said molten polymeric material through a chemicaldepolymerization process in a reactor to produce a depolymerized waxmaterial, wherein said depolymerized wax material has a melting pointbetween 106° C. and 135° C.; adding said depolymerized wax material intoa pre-wax mixture wherein said pre-wax mixture comprises said solidpolymeric post-consumer or post-industrial feed which has not beendepolymerized to produce a modified polymer with an increased melt flowindex, wherein the amount of said depolymerized wax material mixed intosaid pre-wax mixture is between 1 to 5 percent of the weight of saidmodified polymer.